When you go to the salon to have your hair colored, make sure you have a clear idea of what you want -- don't leave all the decisions up the colorist, or you might be disappointed with the results. Educate yourself by doing some research and talking to friends who color their hair. Bring pictures or hair swatches if you have them. The more communication the better: because everyone sees color differently, what's auburn to you could look like strawberry blonde to someone else.
A colorist rarely will refuse to give you the shade you request, even if he or she thinks it's wrong for you. But it's a good idea to take your colorist's advice into consideration -- a well-trained and experienced professional knows what will work with your skin tone and hair type, and whether the color you want is too far from your real shade to look natural.